The front end of a combine harvester normally includes a feed rake, or feeder housing, and a crop-cutting device. The feed rake is pivotally mounted to the harvester housing, and the crop-cutting device is mounted to the feed rake. It is advantageous for the crop-cutting device to be pivotally mounted to and removable from the feed rake.
Typically, the crop-cutting device is mounted to the feed rake by its rear portion, sometimes referred to as a cutterbar trough. U.S. Pat. No. 3,474,606 describes a combine harvester in which the cutterbar trough is pivotally mounted to the feed rake about a horizontal transverse axle located close to the ground. This arrangement allows the angular position of the crop-cutting device to be adjusted relative to the ground. Such adjustment is often made based on the type of crop being harvested. Mechanically or hydraulically controlled adjusting apparatus are linked at one end to the rear wall of the cutterbar trough and to the feeder housing at the other to adjust the angular position of the crop-cutting device. The adjusting apparatus have no load bearing function. The adjusting apparatus pivot the entire crop-cutting device about the horizontal bearing axle. One drawback of the above-described arrangement becomes apparent when the crop-cutting device must be removed from the feed rake. To accomplish this task, the adjusting apparatus and the horizontal bearing axle must first be removed. It is very difficult to do this in the field because the position of the crop-cutting device, when lowered to the ground, will never be exactly parallel to the front axle of the combine harvester due to the ever present unevenness of the ground. Therefore, the horizontal bearing axle, by which the cutterbar trough is connected to the feeder housing, will be at an angle. For this reason a device of this type has not gained general acceptance.
A another arrangement for mounting a crop-cutting device is described in German patent 44 29 384. There hydraulic operating cylinders are provided on the front face of the feed rake. Pick-up hooks are attached to the free ends of the cylinder pistons. Pairs of web plates are rigidly connected to the upper edge of the rear wall of the cutterbar trough of the crop-cutting device. A load-bearing rod is mounted between each pair of web plates. To mount and retain the crop-cutting device on the feed rake of the harvesting machine, the pistons are pulled into the hydraulic cylinders, and the harvesting machine is moved into a pick-up position corresponding to the location of the load-bearing rods. After the load-bearing rods have been caught on the pick-up hooks of the hydraulic cylinders by lifting the feeder housing, and when the rear wall of the cutterbar trough rests on the front face of the feeder housing, a locking bar is pivoted by the machine operator so as to lock the position of the cutterbar trough relative to the feeder housing. This arrangement has the disadvantage that the crop-cutting device can only be adapted to unevenness of the ground in conjunction with the feeder housing. It is not possible to make a special alteration in the angular position of the cutter blade relative to the ground using this device.